A standard container is usually equipped with corner fittings at eight corners thereof to facilitate lifting and stacking operations of the container. Generally twist locks are employed to connect the corner fittings of the neighboring stacked containers together to ensure a safe stacking of containers. Whether containers are stacked in a suitable way is significant for the transport efficiency of a container ship. The external sizes of ISO containers and the positioning dimensions of corner fittings thereof are designed to comply with ISO 668, and therefore ISO containers can make better use of the shipping space of the containership especially designed according to the ISO container sizes.
For non-standard containers with special external sizes or special corner fittings location, there arises a problem that these containers can't make better use of the shipping space of the containership or even are difficult to transport by the containership. To solve the above mentioned problem, bulk ships are used to transport the containers with the special external sizes in bulk. In such a way, technical improvements are needed in a transport ship for transporting the containers with the special external sizes, thereby resulting in an improvement cost and increasing the transportation cost.
Therefore, a new equipment is desired to solve the above-mentioned problem and to reduce the transportation risk.